So above both L1 and L2 are intersecting at node 9. So now how to find this.

We will be taking the Diff approach.

First take the difference of two linked list. i.e. length difference . Like it came 4 , then we can jump as much as difference at once in the longer linked list. Like we can jump 4 nodes directly in the longer linked list. After that we will iterate over the two linked list simultaneously to find the common node.